Integration / RabbitMQ Interview Questions
Explain the lifecycle of a message in RabbitMQ?
A message passes through several distinct stages between the moment a producer creates it and the moment it is finally removed from the broker.
flowchart LR
A[Producer creates message] --> B[Publish to Exchange with routing key]
B --> C{Bindings match?}
C -->|Yes| D["Message copied into matching queue(s)"]
C -->|No| E[Dropped or sent to alternate exchange]
D --> F["Stored in queue; persisted to disk if durable+persistent"]
F --> G[Delivered to a consumer within its prefetch limit]
G --> H{Consumer response}
H -->|ack| I[Message deleted from queue]
H -->|"nack/reject, requeue=false"| J[Dead-lettered or dropped]
H -->|"nack/reject, requeue=true"| F
Two points are worth calling out: a message can be copied into more than one queue if multiple bindings match, and a message can loop back into the "stored in queue" state indefinitely if it keeps being requeued without a TTL or retry limit.
What happens right after a producer publishes a message?
What can happen if a message is repeatedly nacked with requeue=true and no TTL is set?
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